1. Field of the Invention
The present invention relates generally to medical devices which are used to provide access into the human body and, more particularly, to access devices which provide a single, relatively long-term, entry port into the body. The devices each include a detachable hemostasis valve and a nondetachable safety valve to prevent backflow of bodily fluids upon removal of the hemostasis valve.
2. Description of Related Art
A wide variety of medical devices have been developed in recent years for providing access into the human blood stream. These devices have traditionally been divided into two different groups based on their function and purpose. The first group of devices includes catheters which are designed to introduce therapeutic and/or diagnostic fluids into the blood stream. The second group includes devices commonly referred to as xe2x80x9cintroducersxe2x80x9d which are designed to provide an intermediate term access port into the body through which various medical implements may be passed for therapeutic and/or diagnostic purposes. As a generalization, catheters are longer and more flexible than introducers.
Central venous catheters are relatively long tubular devices which have tapered distal tips which are designed for entry into central veins to provide a dedicated route of fluid infusion into the body. The original venous catheters were single lumen devices which provided the ability to infuse a single liquid into the vein at one time. Multiple lumen catheters have since been developed which allow simultaneous introduction of two or more liquids into the vein. The central venous pressure catheter is a type of common multiple lumen catheter which allows the simultaneous introduction and withdrawal of fluids as well as the capability of monitoring blood pressure and other vital parameters. The portion of the catheter which remains outside of the body has been continually refined and redesigned to provide a low profile which increases comfort and reduces the awkwardness associated with a dedicated tube exiting the body.
Introducers are substantially different from catheters in both design and purpose. An introducer is an access device which is intended to provide a dedicated access port into the body. Catheters, on the other hand, are intended to be used to infuse or withdraw fluids from the body. Introducers typically include a relatively short lumen through which various medical implements, including catheters, can be selectively introduced and removed from the body. An important feature of any introducer is the valve assembly. The valve assembly provides a constant seal between the blood stream and the in vitro environment as medical implements are introduced and withdrawn from the body. The valve assembly is typically located outside of the body at the proximal end of the introducer. As a result, the proximal end of introducers has tended to be relatively bulky.
In addition to a valve assembly, many introducers include a side arm at the proximal end. The side arm is connected to the lumen so that fluids can be introduced into the body simultaneously with the medical device. The introducer lumen is considered to be a xe2x80x9csharedxe2x80x9d lumen in that the lumen provides a common conduit for both medical implements and fluid pharmaceuticals or diagnostics.
The currently available introducers and other access devices are well-suited for their intended purpose. However, new medical treatments and diagnostic procedures are continually being developed which require more versatile access into the body. For example, organ transplant procedures and cardiac angioplasty require the introduction of complex combinations of medical implements and diagnostic/therapeutic fluids into the body. Many of the presently available access devices are not well-suited for these relatively complex procedures. As a result, multiple access devices are required which must be located at multiple access sites necessitating multiple entry punctures. Accordingly, there is a continuing need to provide improved access devices that have additional capabilities which increase their versatility and usefulness for the increasing variety of invasive treatments and procedures.
In accordance with the present invention, an improved access device is provided which incorporates a combination of a device lumen valve and a safety valve associated with the device lumen to prevent backflow and leakage of blood from said lumen. In certain embodiments, the present invention is an improvement over existing introducers and other access devices in that multiple lumen access is provided through the introducer in addition to the shared lumen which is used for both medical implements and fluid pharmaceuticals or diagnostics. As an advantage, the improved access device reduces the number of devices required to introduce multiple implements and fluids into the body during complex surgical and diagnostic procedures.
It should be noted that the present invention provides a supplemental safety valve for various vascular access devices, including single or multiple lumen devices. The present disclosure includes a substantial portion of co-pending application Ser. No. 09/329,002, filed Jun. 8, 1999, entitled xe2x80x9cMULTIPLE LUMEN ACCESS DEVICE AND METHOD,xe2x80x9d the disclosure of which is hereby expressly incorporated by reference. This prior application pertains to multiple lumen access devices, broadly defined as having at least one device lumen and at least one auxiliary lumen, typically for infusion. The present supplemental safety valve can be used in combination with many of the embodiments disclosed in the prior application, some of which are included herein as examples. However, the invention can also be used to supplement single lumen access devices, such as standard introducers.
In one exemplary embodiment, the present invention desirably includes a multiple lumen access system for use in providing an entry port into the human body for selectively introducing medical implements therethrough and for providing simultaneous auxiliary access into the body. The system includes a multiple lumen access device comprising an outer tube which has a distal end for introduction into the body and a cross-sectional area. A device lumen through which medical implements may be passed is defined within the cross-sectional area of the outer tube, the device lumen having a distal end and a proximal end. At least one auxiliary lumen is defined within the cross-sectional area and separately from the device lumen, the auxiliary lumen having a distal end and proximal end. Finally, a detachable device lumen valve is associated with the proximal end of the device lumen to provide sealing of the device lumen when medical implements are both present and absent from the device lumen.
A hemostatic safety valve is associated with the device lumen to prevent backflow and leakage of blood from the device lumen when the device lumen valve is purposely or inadvertently detached. Such safety valve may comprise any suitable type of one-way valve or check valve. A particular one-way valve that is useable comprises an elastomeric membrane having a self-sealing opening (e.g. a slit) formed therein. The elastomeric membrane is disposed transversely within the device lumen, or over the proximal end of, the device lumen with its self-sealing opening being biased to a closed or sealed configuration. When no device is inserted through the device lumen, the elastomeric barrier will prevent blood from backflowing in the proximal direction, past the elastomeric barrier, even when the device lumen valve is disconnected or absent. When a device (e.g., another catheter or interventional apparatus) is inserted through the device lumen, it will cause the self-sealing opening of the elastomeric barrier to open sufficiently to allow the device to be inserted therethrough.
A multiple lumen access system according to the present invention may also include ajunction housing having a proximal end and a distal end to which the proximal end of the outer tube connects. The junction housing includes a main channel in fluid communication with the device lumen and at least one auxiliary channel in fluid communication with the at least one auxiliary lumen, the main channel and auxiliary channel(s) diverging from the outer tube to be non-intersecting in the junction housing.
In one embodiment, the main channel and auxiliary channel(s) of the junction housing may be oriented substantially coplanar so that the junction housing is substantially flat, the system further including an extension tube extending from the proximal end of the junction housing and in fluid communication with the main channel wherein the safety valve is connected to the extension tube to therefore be in fluid communication with the main channel. The device lumen valve is then connectable to the safety valve. A side port in the device lumen valve may be provided enabling infusion of fluids to the extension tube and main channel. Furthermore, mating threaded connectors may be included between the device lumen valve and the safety valve enabling easy removal of the device lumen valve. Any appropriate connector, for example a luer connector, may be provided on the device lumen valve, and the system may also include an infusion syringe having a mating luer connector.
The present invention is also directed to a method for introducing medical devices into the body through a single entry port while at all times preventing backflow of fluids through the entry port. In one embodiment, the method includes the steps of providing a vascular access device having a device lumen and a safety valve on the proximal end thereof, introducing the vascular access device into the body with the distal end of the device lumen being positioned within a vasculature of the body; attaching a detachable hemostasis valve to the safety valve to open the safety valve, and inserting a device through the hemostasis valve, open safety valve and device lumen.